Process for rendering synthetic hydrophobic material antistatic and the product obtained therefrom



United States This invention relates to new compositions of matter. Moreparticularly it is concerned with a synthetic, hydrophobic sphapedstructure bearing a novel finish to minimize the accumulation of chargesof static electricity during finishing operations and normal use.

One common disadvantage of synthetic, hydrophobic shaped structures suchas foams, fibers, filaments, yarns, staple, fabric, pellicles and thelike, is that they tend to develop static electrical charges. Thisfeature is objectionable during the manufacture of textiles and in thefinished garment. During manufacturing, static charge from the fibers orfabric interferes with convenient handling during spinning, reeling,weaving, and the like operations. Finished textiles containing suchstructures fail to drape like cotton or wool due to their static chargeand have a tendency to cling uncomfortably to the wearer. Furthermoresuch textiles tend to collect dust and lint. In addition, the electricdischarge itself is bothersome. Most known antistatic agents usefulinthe textile arts lack durability and some impart to textiles undesirableproperties such as unpleasant hand and discoloration upon application orwith continued fabric use. Furthermore, some known antistatic agents areoperable only within a narrow pH range and thus lack compatibility withmany other common yarn-treating agents which are not stable in that pHrange, making it necessary to apply the agent in a treatment stepdistinct from that employed for other purposes.

It is an object of the present invention to provide a composition whichwill impart durable antistatic protec- .tion to a synthetic, hydrophobicshaped structure without causing objectionable changes in otherproperties.

It is another object to provide a water-soluble antistatic compositionwhich is compatible with pH sensitive yarn-finishing ingredients.

A further object is to provide a treated synthetic, hydrophobic shapedstructure which minimizes or eliminates build-up of electrostatic chargeand otherwise possesses substantially the same properties as the samestructure before treatment.

Another object is to provide a process for imparting durable antistaticproperties to a synthetic, hydrophobic shaped structure.

These and other objects will become apparent in the course of thefollowing specification and claims.

In accordance with the present invention a synthetic, hydrophobic shapedstructure which minimizes accumulation of charges of static electricityis provided by epoxide curing at a pH below 7.0 in the presence of anepoxide curing catalyst a synthetic hydrophobic shaped structure bearinga polyamine of the formula:

H [-X-CH CH OCH CHZ) m "O-R-O (CH CH O) -CH' CH ],,X--H (I) wherein -Ris a divalent radical, X is a membei of the class consisting of aminonitrogen and divalent radical terminating in amino nitrogen, m and n aresmall whole numbers from about 3 to about 40 and p is an integer nogreater than about 10. Since the nature of atent R is not criticalprovided it is inert to reaction with amines, it may be any member ofthe class consisting of o o 0 H H 0 g H H I I ll and A- wherein -A-- isa member of the class consisting of divalent aliphatic, alicyclic,aromatic and heterocyclic radicals. Preferably A- is hydrocarbon. Aparticularly desirable class of polyamines are those of the formula: I

whereinX is a member of the class consisting of wherein -R' is a memberof the class consisting of hydrogen, lower alkyl (i.e., an alkyl radicalcontaining less than about 8 carbon atoms in its longest chain) andamino lower alkyl and -Y- is divalent aliphatic which while it maycontain aza linkages is otherwise hydrocarbon, q being a number fromabout 6 to about 40. The preparation of these polyamines is discussed indetail in Belgian Patents 554,506, granted January 25, 1957, and560,446, granted September 14, 1957. In general, the polyethylene glycoldihalide (e.g. chloride, bromide or iodide) analogue is condensed (withrelease of hydrogen halide) with an amine, the nitrogen of whichcontains at least two active hydrogen. Typical of such amines aremethylamine, ethylamine, propylamine, butylamine, amylamine, hexylamine,dodecylamine, alylamine, monoethanolamine, 3-isopropyl-n-propylamine,3-methoxy-npropylamine, diethylenetriamine, bis(3-aminopropyl) amine,bis(2-aminopropyl)amine, hexamethylene diamine, triethylene tetramine,tetraethylene pentamine and the like. Such materials are available onthe open market, typical products corresponding in general to Example 10of Belgian Patent 560,446 and Example 1 of Belgian Patent 554,506.Assignee of the Belgian patent, the Onyx Oil and Chemical Company of 115Morris Street, Jersey City, New Jersey, markets such products under thetrademarks Aston 108 and Aston LT.

By epoxide curing is meant that the polyamine defined above is reacted,after application of the reactants to the said shaped structure, with apolyepoxide. Such materials can be prepared "by condensingepichlorohydrin with a polyol. A typical example is the condensationproduct (with elimination of HCl) of glycerine and epichlorohydrin.Preparation of these products is described in detail in British Patent780,288, dated July 31, 1957. Such a material with a molecular weight ofbetween about 280 to 360 is available on the open market under thetrademark Eponite 100 (viscosity -150 cp. at 25 C.; 10.2 lbs./ gal.) bythe Shell Chemical Corp. of 500 Fifth Avenue, New York, N.Y. Othersimilar commercial products from the same source include the Eponresinswhich are diepoxide condensation products of epichlorohydrin anddimethyl, di-para hydroxyphenyl methane and the poly(allyl glycidylethers). A typical siloxane is l,3-bis- [-3-(2,3-epoxy propoxy) propyl]tetramethyldisiloxane sold under the trade mark Syl-Kern 90 by DowCorning Corp., Midland, Michigan. Reaction of the polyamine (I) or (II)with the polyepoxide'may be conveniently accomplished by heating theshaped structure to which an and 30 parts by volume perchloroethylene2.1 parts by volume dry cleaning soap (sold by R. R. Street 8; Co.,Inc., 569 W. Monroe Street, Chicago,

, Illinois, under the trademark Streets 886) 0.2 part by volume waterAfter tumbling, the fabric is centrifuged for 6 minutes, tumbled for anadditional minutes with an equal amount of fresh, uncharged solvent,then centrifuged again for 5 minutes, dried for 2 minutes at from 6070C. and steam pressed. The bleaching procedure, representative ofprevailing commercial practice, consists of immersing fabric in 100times its weight of bleaching bath containing:

Percent Sodium chlorite .2 Oxalic a .2 Nitric acid .11 Sodium nitrate .5Water 99 heating to boiling, maintaining at boiling for 1 hour, andsubsequently rinsing the fabric in warm water. The bleaching operationis then completed by a scour, i.e., boiling the fabric for 30 minutes in100 times it weight of a detergent mixture consisting of:

Percent Green soap .1 Sodium lauryl sulfate .1 Trisodium phosphate .1

followed by fabric rinsing, dryn'ng,

Durability of antistatic treatments ing, and dry cleaning is determinedby measurement of surface resistances of the fabrics. These measurementsare made under controlled conditions of 25% relative humidity and atemperature of 70 F. Current flowing across, the fabric is measuredaccurately with a Beckman, Model V Micro-microammeter, and the surfaceresistnee is then calculated from this and the known applied voltage.For convenience, these values are reported as logarithms of surfaceresistance. In general, the lower the surface resistance, the lower isthe tendency of the fabric to develop a static charge. Surfacereflectance of undyed fabrics is used as a measure of whiteness.Measurements are made using a Photovolt Model 610 and steam pressing. tobleaching, washreflectometer. By using green, amber, and blue filters,grayness and yellowness can be estimated.

b =m yellowness factor) where B=,refiectance with blue filterG=refiectance with green filter The following examples are cited toillustrate the invention. They are not intended to limit it in any way.Unless otherwise noted, parts as expressed in the examples indicatesparts by weight.

EXAMPLE 1 100 parts of the polyamine formed by condensation ofdiethylene triamine with the dichloride of polyethylene glycol having amolecular weight of 600 (Aston L as identified above) as a 20% solidssolution in water is stirred into 5000 parts of water. The pH of theresulting solution is adjusted to 3.2 by addition of 70 parts of asolution of hydrochloric acid in water. 62 parts of Eponite asidentified above is then added and the mixture is dispersed using aWaring Blender. While mixing in the Waring Blender, 4 parts of zincfluoroborate catalyst as a 40% aqueous solution is added. A slightlyturbid solution is formed.

A swatch of tropical plain weave fabric woven from a polyethyleneterephthalate yarn is dipped into the emulsion prepared as describedabove and squeezed between the rollers of a hand wringer. The fabric isthen cured for 5 minutes in an oven at 160 C. and thereafter scoured for15 minutes at F. The fabric is observed to have gained 3.2% by weight ofantistatic finish based on the original Weight of the fabric. Thetreated fabric has a log R of 10.3 compared with an original log R of14.2. After the standard bleaching the sample is observed to have a logR of 12.9.

A 21% by weight finish based on the Weight of the fabric is attainedwhen 1240 parts of Eponite 100 is employed using the technique describedabove. In this case 80 parts of the zinc fluoroborate catalyst isemployed. The product has a log R of 11.0 before the standard bleachingand a log R of 11.5 after the bleachmg.

EXAMPLE 2 Example 1 is modified by employing as the polyamine componentthe reaction product of the dichloride of polyethylene glycol having amolecular weight of 600 with methylamine (Aston 108 as identifiedabove). The percent by weight of finish picked up by the fabric samplesas Well as log Rs before and after standard bleaching when using 62parts of the diepoxide (A) and when using 1240 parts of the diepoxide(B) are shown in Table 1.

Table 1 Log R Finish, Sample Percent by Wt. Before Alter Bleach Bleach A2. 8 l0. 0 10. 6 B 21. 0 10. 7 11. 7

Sample (B) is found to be waxy and stiff.

EXAMPLE 3 A Waring Blender is employed to mix 500 parts of Aston 108 asa 20% solids solution in water, 100 parts of a 10% aqueous solution ofhydrochloric acid, 62 parts of Eponite 100 and 4 parts of zincfluoroborate catalyst as a 40% aqueous solution. The pH of the resultingmixture is 3.5. The mixture is then stirred into 4340 parts of water.The finish is padded upon four fabric swatches identified in Table II.

The finish is applied using a laboratory padder set at 50 lbs. persquare inch providing t-wo dips and two nips. After padding all fabricsamples are dried overnight at room temperature and thereafter cured for6 minutes at C. The initial log R of the samples, the percent by weightof antistatic agent deposited based on the weight of the fabric and thelog R observations before and after washing, bleaching and dry cleaningare shown in Table III.

Table III Log R Treated Log R (Untreated) Amount Antistat.

(Percent OWF) Sample After a Hrs.

Washing 1 Dry 1 Bleach Clean For comparative purposes swatches of samplefabrics C, D and E above are padded with a solution containing 106 partsof water, 175 parts of an aqueous solution containing 35 parts Aston 108and 17 parts of a 90% aqueous solution of the diiodide of polyethyleneglycol having a molecular weight of 600. The pH is adjusted with sodiumhydroxide to 11.1. After drying at 212 F. fabrics are cured for about 3minutes at 300 F. and thereafter scoured. The amount of finish pickupand the log R before and after and combination of one bleach and onescour are shown in Table IV. Comparative figures for similar samplestreated in accordance with the present invention are included in thetable. The samples treated with the finish cross-linked with thediiodide are labeled C D and E. In addition the table shows acomparative figure of yellowness factor relative to samples C and C Dand D These compare to the yellowness factor of the untreated controlsof 2.02 and 5.8 respectively.

Table IV Amount Antistat.

(Percent OWF Log R Sample Initial 1 Bleach, Yellowness Factor EXAMPLE 4Solutions are made by adding parts of the polyamine of Example 2 as asolids solution in water to 1000 parts of water containing 2.5, 6.2 and12.3 parts respectively, of Epon Resin 562, a condensation product ofepichlorhydrin and glycerine containing 2 epoxy groups per molecule. Toserve as control solutions, Epon Resin 562 is omitted from one solutionof polyethylene glycol amine, and similarly, a 1% solution of Epon Resin562 is prepared, omitting the polyamine. All solutions are acidified topH 2.5 with HCl, including a pure water control containing no otheringredients. Samples of a tow of continuous filaments formed from apolymer of acryolnitrile (i.e. Orlon as identified above) are dippedinto the test solutions at room temperature, wrung out to a solutionpick-up of 100% and cured in a drying oven at 270 F. for ten minutes.The cured tow is converted into staple pads suitable for washing andtesting for antistatic properties.

In this example in determining the durability of the antistaticproperties, washing tests are carried out with 0.1% aqueous Tide using a15-minute wash cycle at 60 C. followed by two 5 minute rinses at 60 C.

To determine the durability of the antistatic properties to drycleaning, quarter-pound staple samples, Wrapped in cheese cloth, arerolled for one-half hour in 13 pounds of Stoddard solvent containing0.75% of dry cleaning soap (Streets 886 detergent). This is followed bytwo 15-minute rinses with pure Stoddard solvent, centrifuging after eachrinse, and air drying.

Table V Finishing Soln. Compn. (per 1000 Log R cc. H2O

Sample Epon Poly- 5 dry 10 dry Resin amine 1 5 10 cleanclean- 562(parts) wash washes washes ings ings (parts) A cationic blue tint whenadded to the compositions employed in treating samples H, I and Jresults in reduction of the color of the samples to less than that ofthe control. In a similar manner optical whiteners and silicone waterproofing agents and other commonly used textile treating agents may besimultaneously applied with the antistatic agents of the presentinvention to perform their conventional roles.

EXAMPLE 5 Examples 1 and 2 are modified by employing as the curing agent62 parts of Syl-Kem 90 as identified above. The log R of the samples Mand N respectively before scouring, after scouring and after 5 hourswash are reported in Table VI.

A polyepoxide resin is prepared by mixing 15 parts of sodium styrenesulfonate, parts of diionized water, 0.15 part of glyceryl monooleate,.08 part of alkyl phenoxy polyoxyethanol and 1.67 parts of glycidylmethacryate in a Waring Blendor to form an emulsion. The emulsion isadded to a 200 ml. 3-necked flask which is then flushed with nitrogen..06 part of a,u-azobisisobutyryl nitrile is then added and the reactionmass is lheated for 3 hours at 70 C. A thick semi-transparent emulsionis formed.

0.5 part of the polyamine, Aston 108, is mixed with 0.5 part of thepolyepoxide resin prepared as identified above to give an aqueousemulsion having 1% solids and the mixture is applied to staple fiberformed from a polymer of acrylonitrile (i.e. Orlon as identified above).The product is observed to have a b of 4.4. The log R values after 1, 5and 10 washings (as described in Example 4) are listed below:

lwashing 10.7 5 washings 12.1 10 washings 13.4

EXAMPLE 7 The technique of Example 4 is followed in preparing threeantistatic finish reactants (M, N and 0) containing the polyamine andpolyepoxide resin in a 1:1 weight ratio. Aston 108 is employed as thepolyamine in each application. The emulsions are applied to a fabricwoven from a polymer of acrylonitrile (i.e. Orlon as identified above)having an initial b;, of 3.0. The identity of the polyepoxide curingagent employed in each example is identified in Table VII. The color andlog R of each sample after curing is reported in Table VIII.

7 Table VII Eponite 100. Epon 815. Poly allyl glycidyl other.

1 A diepoxide condensation product of epichlorohydrin and dimethyldi-para hydroxyphenyl methane.

103 Table VIII Sample b 1 Bleach 5 Washes 1O Washes M 4. s 13.3 13.1 137s N i 3. 9 l3. 6 13. 9 13.9 0 l 13. 3 l3. 6

1 Log R after one wash is 12.6.

EXAMPLE 8 A mixture of 50 parts of Aston 108 active ingredients), 10parts Eponite 100 and 940 parts water is made up and adjusted to pH 3.5.A tow formed from a polymer of acrylonitrile (i.e. Orion as identifiedabove) is treated to provide a 100% by weight wet pickup of thissolution, then cut into staple and dried at 270 F. for ten minutes. 20parts of this treated staple is then blended with 80 parts untreatedstaple and the blend is spun into yarn and woven into a twill fabric.Samples of the fabric are washed, tested, bleached, disperse dyed andbasic dyed. All exhibit static protection after 10 washes as shown inTable IX.

Table IX F 3d Log R l. Sample After 10 washes After l After 10 After 5wash washes dry cleanings 4Q greige fabric 4. 9 12. 5 12. 7 13. 7 0. 7

cotton wool woo By the expression synthetic, hydrophobic shapedstructure is meant a structure such as a foam, fiber, filament, yarn,staple, fabric, pellicle and the like, produced from a syntheticpolymeric material, having a moisture regain of no greater than 5%, suchas a polyamide, a polymer produced from acrylonitrile, a polyester, orthe like. Suitable polyamides are those produced from a linear polymercontaining recurring units of the formula:

wherein Z is a member of the class consisting of a divalent hydrocarbonradical and a divalent radical of the formula ethylenically unsaturatedcompounds which are suitable 75 as the minor constituent in forminguseful copolymers with acrylonitn'le are listed in United States PatentsNos. 2,837,501; 2,486,241 and 2,436,926.

The polyesters from which such structures may be devised includepolyethylene terephthalate, polyethylene terephthalate copolyestersprepared using polyethylene glycols such as polyethylene glycols havingmolecular Weights of to about 6,000, or polyethers such as thedicarboxymethyl acid of polytetramethylene oxide or the esterspolytetramethylene oxide, polydioxalane, or polyesters prepared usingother acids such as bibenzoic, isophthalic or ethylene-bis-p-oxybenzoicacids. Such materials are described in United States Patent No.2,465,319.

Application of the antistatic finish of the present invention may bemade to any form of the shaped structure including foams, fabric, yarn,tow, staple, films, plastic sheeting and the like.

As described previously, the shaped structure is treated With anemulsion of a mixture of a polyepoxide and a compound of Formula I.Generally the emulsion is prepared by dispersing the polyamine and thepolyepoxide in water at room temperature with vigorous stirring. Theconcentration of reactants in the emulsion may vary widely. Aconcentration as high as 20% may be used. However, more dilute emulsionscontaining from about 1 to about 5% of reactants are generallypreferred. Any such finishing suspension having a concentration suitableto provide from about a 0.3% to about a 5% solids pickup based on thedry material is satisfactory. The reaction product can be applied to thestructure by conventional methods such as dipping, padding, brushing,spraying, and the like. After removal of excess liquid, by wringing inthe case of a textile, it is usually convenient to dry and cure thestructure in one operation.

In forming the mixture of reactants the proportion of components mayvary over a wide range. Preferably the ratio of polyamine:polyepoxide ismaintained within the limits of 10:3 to 10:7. Higher ratios ofpolyepoxide such as 1:'l may be used however, as illustrated in theexamples. Larger amounts of the polyepoxide may be employed butgenerally result in a harsher hand.

While, as illustrated above, the reactants may be applied to the shapedstructure without the presence of catalysts, it is preferred to includea minor amount of an epoxide curing catalyst. Such materials not onlyhasten the curing operation or permit curing at lower temperature, butalso increase adherence of the antistatic agent to the structure. Suchmaterials are well known in the art, as described, for instance inUnited States Patent No. 2,752,269. Although the reacted mixture may beeither acidic or alkaline, alkaline conditions usually cause yellowing.

Optimum conditions of curing will depend upon the identity of thereactants, the identity of the textile and whether or not a catalyst isincluded. Room temperature is adequate for forming the cured antistaticfinish when a catalyst is used. Generally, however, a temperature of atleast about 240 F. is preferred to accomplish efiicient drying of thetextile. Usually temperature adiustment is made to permit curing anddrying in a 3- minute interval. A temperature of about 212 F. to 250 F.is recommended for most textile materials. For operation in the absenceof a catalyst at curing cycle of about 10 minutes at 270 F. is adequate.

While applicant does not wish to be bound by any particular theory ofmechanism, it is believed that the curing operation is accomplished byreaction of the epoxide with free hydrogen on the nitrogen of thepolyamine. Thus it has been observed that fabrics treated withpolyamines containing high proportions of active hydrogen (Aston LT) arestiffened to a greater extent upon curing than those where the polyaminehas less free hydrogen (Aston 108).

Many modifications of the above will be obvious to those skilled in theart without a departure from the inventive concept.

What is claimed is:

1. A process of minimizing the accumulation of charge of staticelectricity upon a synthetic, hydrophobic shaped structure whichcomprises applying to the said structure at a pH below 7.0 and in thepresence of an epoxide curing catalyst, a mixture of a polyepoxide and apolyamine of the formula:

wherein R is an organic divalent radical, -X is a member of the classconsisting of amino nitrogen and divalent radical terminating in aminonitrogen, m and n are small whole numbers from about 3 to about 40 and pis an integer no greater than about and thereafter reacting the saidpolyepoxide and the said polyamine together.

2. The process of claim 1 wherein the shaped structure is a textile.

3. A process of minimizing the accumulation of charge of staticelectricity upon a synthetic, hydrophobic shaped structure whichcomprises applying to the said structure at a pH below 7.0 and in thepresence of an epoxide curing catalyst, a mixture of a polyepoxide andpolyamine of the formula:

bon and aza containing alkylene, q is a number from about 6 to about 40and p is an integer no greater than about 10 10 and thereafter reactingthe said polyepoxide and the said polyamine together.

4. The process of claim 3 wherein the shaped structure is a textile.

5. The process of claim 1 wherein the said polyepoxide curing catalystis zinc fluoroborate..

6. The process of claim 3 wherein 7. The process of claim 3 wherein-NY-N- 1i R is divalent ethylene triamine.

8. The process of claim 2 wherein the said textile is a fabric.

9. The process of claim 2 wherein the said textile is a filament.

10. The process of claim 2 wherein the yarn of the said textile isproduced from a polymer of acrylonitrile.

11. The process of claim 2 wherein the yarn of the said textile is apolyamide 12. The process of claim 2 wherein the yarn of the saidtextile is a polyester.

13. The process of claim 1 wherein at least about 0.3% solids based onthe dry material of the epoxide cured polyamine is applied to the saidstructure.

References Cited in the file of this patent UNITED STATES PATENTS2,794,754 Schroeder June 4, 1957 FOREIGN PATENTS 554,506 Belgium Jan.27, 1957

1. A PROCESS OF MINIMIZING THE ACCUMULATION OF CHARGE OF STATICELECTRICITY UPON A SYNTHETIC, HYDROPHOBIC SHAPED STRUCTURE WHICHCOMPRISES APPLYILNG TO THE SAID STRUCTURE AT A PH BELOW 7.0 AND IN THEPRESENCE OF AN EXPOXIDE CURING CATALYST, A MIXTURE OF A POLYEPOXIDE ANDA POLYAMINE OF THE FORMULA: